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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 28 Jun 2023 09:39:33 +0200
Subject: [PATCH 4/4] ARM: vfp: Move sending signals outside of vfp_lock()ed
section.
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
VFP_bounce() is invoked from within vfp_support_entry() and may send a
signal. Sending a signal uses spinlock_t which becomes a sleeping lock
on PREEMPT_RT and must not be acquired within a preempt-disabled
section.
Move the vfp_raise_sigfpe() block outside of the vfp_lock() section.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/arm/vfp/vfpmodule.c | 29 ++++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -268,7 +268,7 @@ static void vfp_panic(char *reason, u32
/*
* Process bitmask of exception conditions.
*/
-static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_regs *regs)
+static int vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr)
{
int si_code = 0;
@@ -276,8 +276,7 @@ static void vfp_raise_exceptions(u32 exc
if (exceptions == VFP_EXCEPTION_ERROR) {
vfp_panic("unhandled bounce", inst);
- vfp_raise_sigfpe(FPE_FLTINV, regs);
- return;
+ return FPE_FLTINV;
}
/*
@@ -305,8 +304,7 @@ static void vfp_raise_exceptions(u32 exc
RAISE(FPSCR_OFC, FPSCR_OFE, FPE_FLTOVF);
RAISE(FPSCR_IOC, FPSCR_IOE, FPE_FLTINV);
- if (si_code)
- vfp_raise_sigfpe(si_code, regs);
+ return si_code;
}
/*
@@ -352,6 +350,8 @@ static u32 vfp_emulate_instruction(u32 i
static void VFP_bounce(u32 trigger, u32 fpexc, struct pt_regs *regs)
{
u32 fpscr, orig_fpscr, fpsid, exceptions;
+ int si_code2 = 0;
+ int si_code = 0;
pr_debug("VFP: bounce: trigger %08x fpexc %08x\n", trigger, fpexc);
@@ -397,8 +397,8 @@ static void VFP_bounce(u32 trigger, u32
* unallocated VFP instruction but with FPSCR.IXE set and not
* on VFP subarch 1.
*/
- vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr, regs);
- return;
+ si_code = vfp_raise_exceptions(VFP_EXCEPTION_ERROR, trigger, fpscr);
+ goto exit;
}
/*
@@ -422,14 +422,14 @@ static void VFP_bounce(u32 trigger, u32
*/
exceptions = vfp_emulate_instruction(trigger, fpscr, regs);
if (exceptions)
- vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
+ si_code2 = vfp_raise_exceptions(exceptions, trigger, orig_fpscr);
/*
* If there isn't a second FP instruction, exit now. Note that
* the FPEXC.FP2V bit is valid only if FPEXC.EX is 1.
*/
if ((fpexc & (FPEXC_EX | FPEXC_FP2V)) != (FPEXC_EX | FPEXC_FP2V))
- return;
+ goto exit;
/*
* The barrier() here prevents fpinst2 being read
@@ -441,7 +441,13 @@ static void VFP_bounce(u32 trigger, u32
emulate:
exceptions = vfp_emulate_instruction(trigger, orig_fpscr, regs);
if (exceptions)
- vfp_raise_exceptions(exceptions, trigger, orig_fpscr, regs);
+ si_code = vfp_raise_exceptions(exceptions, trigger, orig_fpscr);
+exit:
+ vfp_unlock();
+ if (si_code2)
+ vfp_raise_sigfpe(si_code2, regs);
+ if (si_code)
+ vfp_raise_sigfpe(si_code, regs);
}
static void vfp_enable(void *unused)
@@ -773,6 +779,7 @@ static int vfp_support_entry(struct pt_r
* replay the instruction that trapped.
*/
fmxr(FPEXC, fpexc);
+ vfp_unlock();
} else {
/* Check for synchronous or asynchronous exceptions */
if (!(fpexc & (FPEXC_EX | FPEXC_DEX))) {
@@ -794,10 +801,10 @@ static int vfp_support_entry(struct pt_r
}
}
bounce: regs->ARM_pc += 4;
+ /* VFP_bounce() will invoke vfp_unlock() */
VFP_bounce(trigger, fpexc, regs);
}
- vfp_unlock();
return 0;
}
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